[PATCH 5.10 74/93] ipack: ipoctal: fix missing allocation-failure check

From: Johan Hovold <johan@kernel.org>

commit 445c8132727728dc297492a7d9fc074af3e94ba3 upstream.

Add the missing error handling when allocating the transmit buffer to
avoid dereferencing a NULL pointer in write() should the allocation
ever fail.

Fixes: ba4dc61fe8c5 ("Staging: ipack: add support for IP-OCTAL mezzanine board")
Cc: stable@vger.kernel.org      # 3.5
Acked-by: Samuel Iglesias Gonsalvez <redacted>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20210917114622.5412-5-johan@kernel.org (local)
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/ipack/devices/ipoctal.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/ipack/devices/ipoctal.c
+++ b/drivers/ipack/devices/ipoctal.c

@@ -388,7 +388,9 @@ static int ipoctal_inst_slot(struct ipoc
 
 		channel = &ipoctal->channel[i];
 		tty_port_init(&channel->tty_port);
-		tty_port_alloc_xmit_buf(&channel->tty_port);
+		res = tty_port_alloc_xmit_buf(&channel->tty_port);
+		if (res)
+			continue;
 		channel->tty_port.ops = &ipoctal_tty_port_ops;
 
 		ipoctal_reset_stats(&channel->stats);